Study selection

Studies were selected if they were randomised, double blind, placebo controlled trials of probiotic treatment given in combination
with antibiotics and if diarrhoea prevention was reported. Studies of travellers’ diarrhoea and infectious diarrhoea were
excluded.

Data extraction

Data were extracted on sample size; type, dose, and duration of probiotic treatment; and antibiotic studied. The outcome of
interest was prevention of diarrhoea. Diarrhoea was defined as a change from the normal bowel habit with ≥2 loose or watery
stools for ≥2 days.

Conclusion

Commentary

Clinical Associate Professor, College of Nursing University of Arizona Tucson, Arizona, USA

It is well accepted that antibiotic associated diarrhoea occurs in 5–25% of treated patients and that 10–20% of these patients
will have diarrhoea related to Clostridium difficile.1 Most clinicians would also agree that antibiotic associated diarrhoea is a greater problem for certain patients, such as
those <6 years or >65 years of age, or those being cared for in intensive care units. Antibiotic associated diarrhoea is also
more likely to occur in patients receiving aminopenicillins, cephalosporins, or clindamycin. However, the value of probiotics
in preventing antibiotic associated diarrhoea has only recently (since the early 1990s) been clinically addressed.

The study by D’Souza et al may be the only meta-analysis that attempts to clarify the usefulness of probiotics in preventing antibiotic associated diarrhoea
in patients of varying ages using various antibiotics. As such, this review had the potential to provide community and hospital
based clinicians with new information about whether to recommend or, in some cases, prescribe probiotics as concomitant treatment
to antibiotic use.

The methods of the review were rigorous. Unfortunately, only 9 studies were included, and all had relatively small sample
sizes. Furthermore, important characteristics of the interventions varied considerably. The studies differed in the type of
probiotic studied, as well as the dosage and duration of administration. Characteristics of the antibiotics also varied across
studies.

The findings lend some support to the use of probiotics. However, the review fails to provide new insights into which specific
antibiotics should be targeted or which populations may benefit both in terms of health and cost outcomes from the use of
a specific probiotic.

As a result, healthcare providers cannot be certain as to which probiotic to use with which antibiotic in which patient population
to produce the best possible outcomes for the individual patient or the healthcare system in the long term. As indicated by
D’Souza et al, a large, randomised trial of the efficacy of probiotic use in the prevention of antibiotic associated diarrhoea should be
targeted to the elderly. Optimal probiotic dosages and cost-benefits should be addressed.